1. Field of the Invention
Embodiments of the subject matter disclosed herein generally relate to systems, methods and devices capable to automatically perform a low torque low speed test in order to determine whether a rotor of a turbomachinery is free to rotate.
2. Description of Related Art
A cooling process of a turbomachinery starts as soon as the turbomachinery is stopped. The cooling process is not uniform, as an outside of the turbomachinery usually cools faster than its center, where a turbomachinery's rotor is located. Therefore, the rotor may become locked, unable to rotate freely. The locking is transient, disappearing when the cooling is complete. However, sometimes operators need to restart the turbomachinery without waiting for a complete cooling, which is a situation known as a hot restart.
A conventional turbomachinery 1 is illustrated in FIG. 1. In the turbomachinery 1, a rotor inside an axial compressor 10 and a turbine 20 can rotate due to a torque received via an inlet gear box 30. The inlet box 30 is configured to receive a torque from a transfer gear box 40, which is further connected to an accessory gear box 50. The accessory gear box 50 may receive a torque from a maintenance pad 60 or from a starter 80 via an overrunning clutch 70.
In order to make sure that the rotor can rotate freely, thereby to avoid damaging the rotor or other components of the turbomachinery 1, conventionally, prior to a hot restart, an operator tests manually whether the rotor is free to rotate. To do this, the operator enters the turbomachinery's enclosure (not shown) and gains access to the maintenance pad 60 by dismantling a cover of the maintenance pad 60. Then the operator uses a dynamometric tool to apply a torque to the rotor, the torque having value up to a predetermined torque value. The applied torque is transmitted from the accessory gearbox 50 to the rotor of the turbomachinery 1 via the transfer gearbox 40 and the inlet gearbox 30. If the rotor rotates, the test is considered successful. Otherwise, a hot restart is not possible until the turbomachinery 1 cools further, so that the rotor becomes free to rotate. If the test is successful, the operator reassembles the cover of the maintenance pad 60 and leaves the turbomachinery's enclosure.
Such a manual test takes a relative long time. Additionally, it is possible that after the completion of the test, but prior to restarting the turbomachinery, the rotor to become locked since the cooling continues.
Accordingly, it would be desirable to provide systems and methods that avoid the afore-described problems and drawbacks.